In the 1990s, the TRA was facing an aging fleet of local trains, all of which did not feature air conditioning.

Therefore, in 1993, the company entered a contract with South Korean manufacturer Daewoo to build 344 cars, which would be arranged all into 86 trainsets.

The destination signs have black text over a white background, which is inverted from the EMU400 series; this was updated to an LED display in 2004–2005.

The cars originally had one step at each door; this was removed beginning in 2017 by raising platforms and remodeling the interior to turn the trains into a low floor layout for accessibility.

[5] On 8 July 2016, a bomb was detonated within a northbound EMU550 train number 1258 near Songshan station, injuring 25 people.